1. Field of the Invention
The present invention relates to a method of measuring a mobility of a terminal based on a received signal strength (RSS) in a wireless communication system, and a method and apparatus for handover based on the measured mobility.
2. Description of the Related Art
A terminal using wireless communication may move in any direction within a scope of a communication service. However, when the terminal desires to be out of the scope of a network currently accessed by the terminal, the terminal may require a handover so as to continuously perform communication although the terminal is out of the scope. In this example, when the mobility of the terminal is measured, a target base station to which the terminal is to be handed over may be determined in advance, so that the target base station may readily prepare radio resources to be allocated to the terminal, in advance. Also, a number of handovers completed to a network of an undesired base station may be reduced.
A ping-pong effect refers to a case where a terminal, which stays in a cell edge after being handed over to a predetermined network, is handed over back to a previous network or to a case where handover of a terminal placed at a cell edge is repeatedly performed since a handover determining index moves back and forth over a threshold. When the ping-pong effect occurs, a load in a network may increase due to a path update and signaling based on frequent handover. Also, when a handover is performed before the path update associated with a previous handover is completed, a delay and loss of packet may occur.
A ping-pong effect refers to a case where a terminal, which stays in a cell edge after being handed over to a predetermined network, is handed over back to a previous network or to a case where handover of a terminal placed at a cell edge is repeatedly performed since a handover determining index moves back and forth over a threshold. When the ping-pong effect occurs, a load in a network may increase due to a path update and signaling based on frequent handover. Also, when a handover is performed before the path update associated with a previous handover is completed, a delay and loss of packet may occur.
The third generation partnership project (3GPP) provides a handover hysteresis margin (HOM) scheme and a handover time-to-trigger (TTT) scheme so as to reduce a drawback caused by the ping-pong effect in a long-term evolution (LTE)-Advanced network, which is a next generation mobile communication standard. However, both the HOM scheme and the TTT scheme may not include a mobility of a terminal.